Assuming you have a good seal, you'll usually get bbbles within 24 hours - but the stick here says it can be up to 72.
How much yeast you pitched, the makeup of your wort, the temperature, the strain of yeast, all have impact on the time that fermentation starts.
And yeah, just leave it alone for a couple of weeks. Don't pull your lid off and snap a pic in two days to show us how ugly it is and create a new "is this infected?" thread. Fermentation is ugly, can be stinky, etc.